An axial rotor section of this generic type for a turbine, and a rotor of this generic type, are disclosed, for example, in Laid-Open Specification DE 1 963 364. The rotor section is formed by a rotor disk and is equipped with holding grooves, which run in the axial direction, for the turbine rotor blades, with an endlessly circumferential holding groove for sealing plates being provided at the end. A plurality of projections are provided on one side wall of the retaining groove, are distributed uniformly in the circumferential direction and partially cover the groove base on the retaining groove. Furthermore, the laid-open specification discloses a sealing plate in the form of a plate which, adjacent to its inner edge that is arranged radially inwards, has a thickened area on both sides which corresponds approximately to the groove width of the retaining groove. The thickened area is in this case interrupted in places, viewed in the circumferential direction, by recesses which are designed with a width that corresponds to that of the projections of the retaining groove. In consequence, the sealing plate can be inserted into the retaining groove from the outside by a purely radial movement and, following a movement in the circumferential direction which corresponds approximately to the width of the projection, is hooked thereto. The thickened area of sealing plate then engages behind the projections on the retaining groove, so that the sealing plate cannot move outwards. In order to fit all the sealing plates, they are successively inserted into the retaining groove and only then can they be moved jointly in the circumferential direction. This avoids the need for a sealing plate lock. After insertion and movement of the sealing plates, the rotor blades are pushed into their grooves. The outer edge of the sealing plates are then pushed into grooves on the platform side of the rotor blades so that they are secured against axial movement. In order to complete the assembly process, the sealing plates are fixed in a raised position by means of a screw. Each widened area then rests on the projection. This arrangement of the components makes it possible to separate a first area, which is located between the sealing plate and the end face of the rotor disk, from a second area, which is located beyond the sealing plate, for guiding different media. In order to achieve particularly good sealing, the widened area of the sealing plate rests on that side wall of the retaining groove on which no projection is provided. Furthermore, an inner, conically running edge of the projection ensures that the sealing plate is pressed against that side wall of the retaining groove which has no projection, by the influence of centrifugal force.
One disadvantage of the known arrangement is the complex design of the side surfaces of the rotor disk and of the sealing plate, with projections and recesses. A further disadvantage is the use of a screw to secure the sealing plates against movement in the circumferential direction. Corrosion and strength problems can occur in the screw connection as a result of the alternating thermal stress that occurs between operation and shutdown and as a result of the hot gas flowing through the turbine. In some circumstances, this screw connection cannot be released correctly. In this situation, the screw is drilled out, with this process generally also being carried out on the rotor while it is still located in the lower housing half of the gas turbine. During this process, it is possible for swarf to fall into the lower housing half, which can lead to inadvertent contamination during subsequent operation.
Furthermore, FR 2 524 933 discloses a means for securing rotor blades against axial movement, with the rotor blades being held by means of a plate which can move in the circumferential direction. However, the arrangement disclosed in this document is not suitable for sealing an area close to the disk from an area beyond the plate.
Furthermore, laid-open specification DE 30 33 768 A1 discloses a rotor assembly for a rotor disk of a turbine which has an integral sealing ring in order to secure the rotor blades axially. However, because of the integral sealing ring, this is suitable only for aircraft gas turbines since these are formed by stacks in the axial direction. In contrast, stationary gas turbines are composed of two housing halves which surround the completely assembled rotor. The integral sealing ring in DE 30 33 768 A1 is hooked to the turbine disk in the form of a bayonet fitting. For this purpose, projections and recesses, which are distributed along the circumference, are arranged alternately both on the turbine disk and on the sealing ring. For assembly, the sealing ring is placed on the rotor disk, with the recesses and projections opposite one another. These can then be hooked to one another by slightly twisting the two parts with respect to one another.